The present invention relates generally to door and window arrangements for use in buildings and other static structures. More particularly, this invention relates to insulative interior window assemblies that can be installed onto pre existing exterior window assemblies.
Prior to the present increased concern over energy efficiency and cost savings in building maintenance, many buildings, both residential and commercial, were construed with only a single prime or exterior window assembly in the window openings. Further, these window assemblies were often arranged to substantially fill the window opening, leaving little or no room for venetian blinds or shades to be mounted within the window opening. Also, such prior exterior window assemblies often included window panes that were movable in a non vertical direction, such as with awning or casement windows.
In the present time, in order to decrease thermal loses through the window openings and thereby increase the desirability and livability of these older buildings, it has been suggested to employ either interior or exterior storm windows. Exterior storm windows are typically mounted on the outside of the building at the peripheral facing of the window opening to cover the prime window assembly and shield it from the environment. Such arrangements have served to provide improved insulation, but are also subject to certain drawbacks.
To avoid accumulation of condensation between the exterior storm window and the prime window, weep holes or gaps leading from the exterior environment into the space between these windows are typically provided. Thus, an air tight seal is not formed around the exterior storm window to maximize the insulative potential. Further, such storm windows are usually constructed of rigid, weather resistant materials, such as aluminum or other metals. These materials have relatively high thermal conductivity and, as a result, do not permit maximum energy efficiency. Also, exterior storm windows can be difficult to install and require expensive, professional installation, especially where ground plantings surround the window opening and/or at higher window elevations. In some commercial buildings the window elevations are so extreme that exterior storm windows are not available at all as a practical matter. With certain historic buildings and condominium dwellings, use of exterior storm windows is prohibited by law or restrictive covenant. Even when such storm windows can be readily installed, to apply them over casement or awning windows typically severally restricts or entirely eliminates the workability of those prime windows. Also, the workability of the vertically oriented double hung window panes of typical exterior storm windows is adversely affected by the "free fall" mounting often employed for those panes.
So called "interior storm windows" are typically mounted inside the building within the window opening. Such storm windows have, for example, been held in place by magnetic strips or guide tracks secured to the window opening frame directly adjacent the prime window. Interior storm windows can be employed at all building elevations and are substantially unnoticeable from the building exterior, thus overcoming many of the limitations on usage of exterior storm windows. Further, not needing to be as weather resistant, interior storm windows can be constructed of materials which are less thermally conductive.
However, interior storm windows typically require careful, on site measurement of each window and largely custom construction often with professional assistance. Finish trim often needs to be cut and stained at the site and installed separately from the storm window. Further, interior storm windows often interfere with window hardware, such as handles and cranks for casement or awning windows. Thus, the hardware must be removed and those prime windows rendered inoperative if the interior storm window is to be installed. Likewise, since the interior storm window is mounted within the window opening, its mounting frame and panes restrict access to the prime window for cleaning and/or removal of prime window panes. Similarly, in window openings of lesser depth, use of interior storm windows can preclude use of a venetian blind or shade between the prime and storm windows. Such between window mountings of blinds would otherwise be desirable to decrease the accumulation of dust on the blinds.
Accordingly, it is an object of the present invention to provide an improved interior mounted, insulative window assembly. Other objects include the provision of interior window assembly:
1. having low construction and installation costs, PA1 2. which does not restrict prime window operation, particularly for casement and/or awning windows, PA1 3. permitting high thermal efficiency and having reduced through-window heat loss, PA1 4. which allows complete access to the prime window for cleaning or pane removal, PA1 5. which can be prefabricated as an attractive, integral unit with decorative trim, PA1 6. permitting between window mounting of venetian blinds or shades.
These and other objects of the present invention are attained by an interior insulative window mounted outside of the prime window opening to the window opening frame and/or adjacent wall surface. This interior window is internally formed with decorative trim off-site and installed as a single unit which does not penetrate the window opening. The mounting frame can optionally include mounting space for receiving a venetian blind to be retained between the prime window and the interior window. For decorative consistency and/or further thermal efficiency, the corresponding structure can be applied to sliding patio doors.
Other objects, advantages and novel features of the present invention will further become readily apparent from the drawings and detailed description below.